1. Field of the Invention
The present invention relates generally to aerosol generators and, more particularly, to aerosol generators which include a heater in a multilayered composite. The aerosol generators of the invention are able to generate aerosols without requiring the use of compressed gas propellants. The present invention also relates to methods for generating an aerosol. The present invention has particular applicability to the generation of aerosols containing medicated material.
2. Description of the Related Art
Aerosols are gaseous suspensions of fine solid or liquid particles and are useful in a wide variety of applications. For example, medicated liquids and powders may be administered in aerosol form. Such medicated aerosols include, for example, materials which are useful in the treatment of respiratory ailments, in which case the aerosols may be inhaled into a patient""s lungs. Aerosols may also be used in non-medicinal applications including, for example, dispensing air fresheners and insecticides and delivering paints and/or lubricants.
In aerosol inhalation applications, it is typically desirable to provide an aerosol having an average mass median particle diameter of less than 2 microns to facilitate deep lung penetration. Most known aerosol generators are incapable of generating aerosols having an average mass median particle diameter less than 2 microns. Also, in certain applications, it is generally desirable to deliver medicated material at high flow rates, for example, above 1 mg per second. Most known aerosol generators suited for delivering medicated material are incapable of delivering material at such high flow rates while maintaining a suitable average mass median particle diameter. In addition, most known aerosol generators deliver an imprecise amount of aerosol compared with the amount of aerosol that is intended to be delivered.
The related art discloses aerosol generators which employ various techniques for delivering an aerosol. A particularly useful technique involves volatilizing a fluid and ejecting the volatilized fluid into the atmosphere. The volatilized fluid subsequently condenses, thereby forming an aerosol. See, for example, commonly assigned U.S. Pat. No. 5,743,251, the entire contents of which document are hereby incorporated by reference. Such aerosol generators may eliminate or conspicuously reduce some or all of the aforementioned problems associated with the known aerosol generators. However, since these aerosol generators employ heat-generating systems, heat resistive material and, in some cases, various control devices, pumps and valves, the manufacture and assembly of such aerosol generators can be complicated and expensive.
In light of the foregoing, there exists a need in the art for the provision of an aerosol which overcomes or conspicuously ameliorates the above described shortcomings in the related art. Accordingly, it is an object of the present invention to provide an aerosol generator having a heater in a multilayered composite, and which produces an aerosol from a fluid by volatilizing the fluid and directing the volatilized fluid therefrom.
It is a further object of the present invention to provide a method for generating an aerosol.
Other objects and aspects of the present invention will become apparent to one of ordinary skill in the art upon review of the specification, drawings and claims appended hereto.
The foregoing objects are met by the aerosol generators of the present invention. According to a first aspect of the present invention, an aerosol generator is provided. The aerosol generator includes:
(a) a fluid passage arranged between a first layer and a second layer, wherein the first and second layers at least partially define the fluid passage;
(b) a fluid supply arranged to provide a fluid in liquid phase to the fluid passage;
(c) a heater arranged to volatilize the fluid in the fluid passage; and
(d) an outlet arranged to receive the volatilized fluid and direct the volatilized fluid out of the fluid passage.
According to another aspect of the present invention, a method for generating an aerosol using an aerosol generator comprising (1) a fluid passage arranged between a first layer and a second layer, wherein the first and second layers at least partially define the fluid passage; (2) a fluid supply arranged to provide a fluid in liquid phase to the fluid passage; (3) a heater arranged to volatilize the fluid in the fluid passage; and (4) an outlet arranged to receive the volatilized fluid and direct the volatilized fluid out of the fluid passage, the method comprising:
(a) heating the heater of the aerosol generator, thereby volatilizing the fluid in the fluid passage; and
(b) directing the volatilized fluid out of the fluid passage via the outlet.